Consciousness

Representation of consciousness from the 17th century.

See also: Conscience

Further information: Philosophy of mind

Consciousness is variously defined as subjective experience, awareness, the ability to experience "feeling", wakefulness, the understanding of the concept "self", or the executive control system of the mind. It is an umbrella term that may refer to a variety of mental phenomena. Although humans realize what everyday experiences are, consciousness has been difficult to define, philosophers note (e.g. John Searle in The Oxford Companion to Philosophy):

"Anything that we are aware of at a given moment forms part of our consciousness, making conscious experience at once the most familiar and most mysterious aspect of our lives."

— Schneider and Velmans, 2007

Consciousness in medicine (e.g., anesthesiology) is assessed by observing a patient's alertness and responsiveness, and can be seen as a continuum of states ranging from alert, oriented to time and place, and communicative, through disorientation, then delirium, then loss of any meaningful communication, and ending with loss of movement in response to painful stimuli.

Consciousness in psychology and philosophy typically means something beyond what it means for anesthesiology, and may be said in many contexts to imply four characteristics: subjectivity, change, continuity, and selectivity. Philosopher Franz Brentano has suggested intentionality or aboutness (that consciousness is about something). However, within the philosophy of mind there is no consensus on whether intentionality is a requirement for consciousness.

Consciousness is the subject of much research in philosophy of mind, psychology, neuroscience, cognitive science and artificial intelligence. There are conferences devoted to it including the Association for the Scientific Study of Consciousness, the Towards a Science of Consciousness conferences in Tucson and now the Online Consciousness Conference. Issues of practical concern include how the presence of consciousness can be assessed in severely ill or comatose people; whether non-human consciousness exists and if so how it can be measured; at what point in fetal development consciousness begins; and whether computers can achieve a conscious state.

Etymology

The English word "conscious" is derived from Latin conscius (con- "together" + scire "to know"), but the Latin version did not have the same meaning as our word — it meant knowing with, in other words having joint or common knowledge with another, privy to, cognizant of. There were, however, many occurrences in Latin writings of the phrase conscius sibi, which translates literally as "knowing with oneself", or in other words sharing knowledge with oneself about something. Taken literally this is nonsense, but it had the figurative meaning of knowing that one knows, as the modern English word "conscious" does. In its earliest uses in the 1500s, the English word retained the Latin meaning. For example Thomas Hobbes in Leviathan wrote: "Where two, or more men, know of one and the same fact, they are said to be Conscious of it one to another." The Latin conscius sibi was rendered in English as "conscious to oneself" or "conscious unto oneself". For example, Archbishop Ussher wrote in 1613 of "being so conscious unto myself of my great weakness".

A related word was conscientia, which primarily means moral conscience. In the literal sense, "conscientia" means knowledge-with, that is, shared knowledge. The word first appears in Latin juridical texts by writers such as Cicero. Here, conscientia is the knowledge that a witness has of the deed of someone else. René Descartes (1596–1650) is generally taken to be the first philosopher to use "conscientia" in a way that does not fit this traditional meaning. Descartes used "conscientia" the way modern speakers would use "conscience." In Search after Truth he says "conscience or internal testimony" (conscientia vel interno testimonio).

Shortly thereafter, in Britain, the neo-Platonist theologian Ralph Cudworth used something resembling the modern meaning of consciousness in his "True Intellectual System of the Universe" (1678), although he never explicitly defined the term. The origin of the modern concept of consciousness is often attributed to John Locke's Essay Concerning Human Understanding, published in 1690. Locke explicitly defined consciousness as “the perception of what passes in a man’s own mind.” His essay had much influence on the 18th century view of consciousness, and his definition appeared in Samuel Johnson's celebrated Dictionary (1755).

Philosophical approaches

There are many philosophical stances on consciousness, including behaviorism, dualism, idealism, functionalism, reflexive monism, phenomenalism, phenomenology and intentionality, physicalism, emergentism, mysticism, personal identity, and externalism.

Phenomenal and access consciousness

Phenomenal consciousness (P-consciousness) is simply experience; it is moving, colored forms, sounds, sensations, emotions and feelings with our bodies and responses at the center. These experiences, considered independently of any impact on behavior, are called qualia. The hard problem of consciousness, formulated by David Chalmers in 1996, deals with the issue of "how to explain a state of phenomenal consciousness in terms of its neurological basis".

Access consciousness (A-consciousness) is the phenomenon whereby information in our minds is accessible for verbal report, reasoning, and the control of behavior. So, when we perceive, information about what we perceive is often access conscious; when we introspect, information about our thoughts is access conscious; when we remember, information about the past (e.g., something that we learned) is often access conscious, and so on. Chalmers thinks that access consciousness is less mysterious than phenomenal consciousness, so that it is held to pose one of the easy problems of consciousness. Daniel Dennett denies that there is a "hard problem", asserting that the totality of consciousness can be understood in terms of impact on behavior, as studied through heterophenomenology. There have been numerous approaches to the processes that act on conscious experience from instant to instant. Dennett suggests that what people think of as phenomenal consciousness, such as qualia, are judgments and consequent behavior. He extends this analysis by arguing that phenomenal consciousness can be explained in terms of access consciousness, denying the existence of qualia, hence denying the existence of a "hard problem." Chalmers, on the other hand, argues that Dennett's explanatory processes merely address aspects of the easy problem. Eccles and others have pointed out the difficulty of explaining the evolution of qualia, or of 'minds', which experience them, given that all the processes governing evolution are physical and so have no direct access to them. There is no guarantee that all people have minds, nor any way to verify whether one does or does not possess one.

Events that occur in the mind or brain that are not within phenomenal or access consciousness are known as subconscious events.

The description and location of phenomenal consciousness

For centuries, philosophers have investigated phenomenal consciousness. René Descartes, who coined the famous dictum 'cogito ergo sum', wrote Meditations on First Philosophy in the seventeenth century. According to Descartes, all thought is conscious. Conscious experience, according to Descartes, included such ideas as imaginings and perceptions laid out in space and time that are viewed from a point, and appearing as a result of some quality such as color, smell, and so on.

Descartes defines ideas as extended things, as in this excerpt from his Treatise on Man:

Now among these figures, it is not those imprinted on the external sense organs, or on the internal surface of the brain, which should be taken to be ideas - but only those that are traced in the spirits on the surface of gland H [where the seat of the imagination and the 'common sense' is located]. That is to say, it is only the latter figures which should be taken to be the forms or images which the rational soul united to this machine will consider directly when it imagines some object or perceives it by the senses.

Thus Descartes does not identify mental ideas with activity within the sense organs, or even with brain activity, but rather with the "forms or images" that unite the body and the "rational soul," through the mediating 'gland H'. This organ is now known as the pineal gland. Descartes notes that, anatomically, while the human brain consists of two symmetrical hemispheres the pineal gland, which lies close to the brain's centre, appears to be singular. Thus he extrapolated from this that it was the mediator between body and soul.

Philosophical responses, including those of Nicolas Malebranche, Thomas Reid, John Locke, David Hume and Immanuel Kant, were varied. Malebranche, for example, agreed with Descartes that the human being was composed of two elements, body and mind, and that conscious experience resided in the latter. He did, however, disagree with Descartes as to the ease with which we might become aware of our mental constitution, stating 'I am not my own light unto myself'. David Hume and Immanuel Kant also differ from Descartes, in that they avoid mentioning a place from which experience is viewed; certainly, few if any modern philosophers have identified the pineal gland as the seat of dualist interaction.

When we look around a room or have a dream, things are laid out in space and time and viewed as if from a point. However, when philosophers and scientists consider the location of the form and contents of this phenomenal consciousness, there are fierce disagreements. As an example, Descartes proposed that the contents are brain activity seen by a non-physical place without extension (the Res Cogitans), which, in Meditations on First Philosophy, he identified as the soul. This idea is known as Cartesian Dualism. Another example is found in the work of Thomas Reid who thought the contents of consciousness are the world itself, which becomes conscious experience in some way. This concept is a type of Direct realism. The precise physical substrate of conscious experience in the world, such as photons, quantum fields, etc. is usually not specified.

Other philosophers, such as George Berkeley, have proposed that the contents of consciousness are an aspect of minds and do not necessarily involve matter at all. This is a type of Idealism. Yet others, such as Leibniz, have considered that each point in the universe is endowed with conscious content. This is a form of Panpsychism, the belief that all matter, including rocks for example, is sentient or conscious. The concept of the things in conscious experience being impressions in the brain is a type of representationalism, and representationalism is a form of indirect realism.

It is sometimes held that consciousness emerges from the complexity of brain processing. The general label 'emergence' applies to new phenomena that emerge from a physical basis without the connection between the two explicitly specified.

Some theorists hold that phenomenal consciousness poses an explanatory gap. Colin McGinn takes the New Mysterianism position that it can't be solved, and Chalmers criticizes purely physical accounts of mental experiences based on the idea that philosophical zombies are logically possible and supports property dualism. But others have proposed speculative scientific theories to explain the explanatory gap, such as Quantum mind, space-time theories of consciousness, reflexive monism, and Electromagnetic theories of consciousness to explain the correspondence between brain activity and experience.

Parapsychologists and some philosophers e.g. Stephen Braude sometimes appeal to the concepts of psychokinesis or telepathy to support the belief that consciousness is not confined to the brain.

Philosophical criticisms

Nietzsche, for his part, once wrote that "they give you free will only to later blame yourself", thus reversing the classical liberal conception of free will in a critical account of the genealogy of consciousness as the effect of guilt and ressentiment, which he described in On the Genealogy of Morals. Hence, Nietzsche was the first one to make the claim that the modern notion of consciousness was indebted to the modern system of penalty, which judged a man according to his "responsibility", that is by the consciousness through which acts can be attributed to an individual subject: "I did this! This is me!". Consciousness is thus related by Nietzsche to the classic philosopheme of recognition which, according to him, defines knowledge.

Michel Foucault's analysis of the creation of the individual subject through disciplines, in Discipline and Punish (1975), would extend Nietzsche's genealogy of consciousness and personal identity - i.e. individualism - to the change in the juridico-penal system: the emergence of penology and the disciplinization of the individual subject through the creation of a penal system that judged not the acts as it alleged to, but the personal identity of the wrong-doer. In other words, Foucault maintained that, by judging not the acts (the crime), but the person behind those acts (the criminal), the modern penal system was not only following the philosophical definition of consciousness, once again demonstrating the overlap between ideas and social institutions ("material ideology" as Althusser would call it); it was by itself creating the individual person, categorizing and dividing the masses into a category of poor but honest and law-abiding citizens and another category of "professional criminals" or recidivists.

Gilbert Ryle has argued that traditional understandings of consciousness depend on a Cartesian outlook that divides into mind and body, mind and world. He proposed that we speak not of minds, bodies, and the world, but of individuals, or persons, acting in the world. Thus, by saying 'consciousness,' we end up misleading ourselves by thinking that there is any sort of thing as consciousness separated from behavioral and linguistic understandings.

The failure to produce a workable definition of consciousness also raises formidable philosophical questions. It has been argued that when Antonio Damasio defines consciousness as "an organism's awareness of its own self and its surroundings", the definition has not escaped circularity, because awareness in that context can be considered a synonym for consciousness.

The notion of consciousness as passive awareness can be contrasted with the notion of the active construction of mental representations. Maturana and Varela showed that the brain is massively involved with creating worlds of experience for us with meager input from the senses. Evolutionary biologist Richard Dawkins sums up the interactive view of experience: "In a way, what sense organs do is assist our brains to construct a useful model and it is this model that we move around in. It is a kind of virtual reality simulation of the world."

Consciousness and language

Because humans express their conscious states using language, it is tempting to equate language abilities and consciousness. There are, however, speechless humans (infants, feral children, aphasics, severe forms of autism), to whom consciousness is attributed despite language lost or not yet acquired. Moreover, the study of brain states of non-linguistic primates, in particular the macaques, has been used extensively by scientists and philosophers in their quest for the neural correlates of the contents of consciousness.

Julian Jaynes argued to the contrary, in The Origin of Consciousness in the Breakdown of the Bicameral Mind, that for consciousness to arise in a person, language needs to have reached a fairly high level of complexity. According to Jaynes, human consciousness emerged as recently as 1300 BCE or thereabouts. He defines consciousness in such a way as to show how he conceives of it as a type of thinking that builds upon non human ways of perceiving, for example (p. 55)...

Subjective conscious mind is an analog of what is called the real world. It is built up like a vocabulary or lexical field whose terms are all metaphors or analogs of behavior in the physical world. Its reality is of the same order as mathematics. It allows us to shortcut behavioral processes and arrive at more adequate decisions. Like mathematics, it is an operator rather than a repository. And it is intimately bound up with volition and decision.

...and page 65...

It operates by way of analogy, by way of constructing an analog space with an analog "I" that can observe that space, and move metaphorically in it.

...and perhaps most tellingly, page 66...

there is nothing in consciousness that is not an analog of something that was in behavior first.

Some philosophers, including W.V. Quine, and some neuroscientists, including Christof Koch, contest this hypothesis, arguing that it suggests that prior to this "discovery" of consciousness, experience simply did not exist. Ned Block argued that Jaynes had confused consciousness with the concept of consciousness, the latter being what was discovered between the Iliad and the Odyssey. Daniel Dennett states that these approaches misconceive Jaynes's definition of consciousness as more than mere perception or awareness of an object. He notes that consciousness is like money in that having the thing requires having the concept of it, so it is a revolutionary proposal and not a ridiculous error to suppose that consciousness only emerges when its concept does.

More recently, Merlin Donald, seeing a similar connection between language and consciousness, and a similar link to cultural, and not purely genetic, evolution, has put a similar proposal to Jaynes' forward - though relying on less specific speculation about the more recent pre-history of consciousness. He writes...

To understand consciousness fully, the generation of culture must be explained. Enculturation has been neglected as a possible formative process in its own right, but we have no alternative other than to give it pride of place in any evolutionary theory.

He argues that an earlier "symbol using culture" must have preceded both the personal symbol using of individual consciousness, as well as language itself.

The idea that language and consciousness are not innate to humans, a characteristic of human nature, but rather the result of cultural evolution, beginning with something similar to the culture of chimpanzees, goes back before Darwin to Rousseau's Second Discourse.

Vedanta

According to Vedanta, awareness is not a product of physical processes and can be considered under four aspects. The first is waking consciousness (jagaritasthana), the identification with “I” or “me” in relationship with phenomenal experiences with external objects. The second aspect is dream consciousness (svapna-sthana), which embodies the same subject/object duality as the waking state. The third aspect of consciousness is deep sleep (susupti), which is non-dual as a result of holding in abeyance all feelings, thoughts, and sensations. The final aspect is the consciousness that underlies and transcends the first three aspects (turiya) also referred to as a trans-cognitive state (anubhava) or a state of self-realization or freedom from body-mind identification (moksha). Gaudiya Vedanta recognizes a fifth aspect of consciousness in which God becomes subordinate to bhakti.

Vijñāna

In Buddhism, consciousness (viññāṇa) is included in the five classically defined experiential "aggregates". The aggregates are seen as empty of self-nature; that is, they arise dependent on causes and conditions. The cause for consciousness arising (viññāṇa) is the arising of another aggregate (physical or mental); and, consciousness arising in turn gives rise to one or more of the mental (nāma) aggregates. The causation chain identified in the aggregate (khandha) model overlaps the conditioning chain in Dependent Origination (paticcasamuppāda) model. Consciousness is the third link, between mind body mental formations and name & form in the traditional Twelve Causes (nidāna) of Dependent Origination. The six classes of consciousness are: eye-consciousness, ear-consciousness, nose-consciousness, tongue-consciousness, body-consciousness, intellect-consciousness. The following aspects are traditionally highlighted within Dependent Origination:

• consciousness is conditioned by mental fabrications (saṅkhāra);
• consciousness and the mind-body (nāmarūpa) are interdependent; and,
• consciousness acts as a "life force" by which there is a continuity across rebirths.

Scientific approaches

Cognitive psychology and cognitive neuroscience

For a long time in scientific psychology, consciousness as a research topic or explanatory concept was strongly discouraged by mainstream scholars, because of concerns about the validation of primary data . Research on topics associated with consciousness were conducted under the banner of attention. Modern investigations into consciousness are based on psychological statistical studies and case studies of consciousness states and the deficits caused by surgery, trauma or illness that disrupt the normal functioning of human senses and cognition. Another approach is experimental work on unconscious perception, e.g., the investigation of priming effects using subliminal stimuli. These discoveries suggest that the mind is a complex structure derived from various localized functions that are bound together with a unitary awareness.

Several studies point to common mechanisms in different clinical conditions that lead to loss of consciousness. Persistent vegetative state (PVS) is a condition in which an individual loses the higher cerebral powers of the brain, but maintains sleep-wake cycles with full or partial autonomic functions. Studies comparing PVS with healthy, awake subjects consistently demonstrate an impaired connectivity between the deeper (brainstem and thalamic) and the upper (cortical) areas of the brain. In addition, it is agreed that the general brain activity in the cortex is lower in the PVS state. Some electroneurobiological interpretations of consciousness characterize this loss of consciousness as a loss of the ability to resolve time (similar to playing an old phonographic record at very slow or very rapid speed), along a continuum that starts with inattention, continues on sleep, and arrives to coma and death . It is likely that different components of consciousness can be teased apart with anesthetics, sedatives and hypnotics. These drugs appear to act differently on several brain areas to disrupt, to varying degrees, different components of consciousness. The ability to recall information, for example, may be disrupted by anesthetics acting on the hippocampal cortex. Neurons in this region are particularly sensitive to anesthetics at the time loss of recall occurs. Direct anesthetic actions on hippocampal neurons have been shown to underlie EEG effects that occur in humans and animals during loss of recall.

Brain chemistry affects human consciousness. Sleeping drugs such as midazolam (Dormicum) can bring the brain from the awake condition (conscious) to the sleep (unconscious) condition. Wake-up drugs such as flumazenil reverse this process. Many other drugs (such as alcohol, nicotine, Tetrahydrocannabinol (THC), heroin, cocaine, LSD, MDMA, caffeine), have a consciousness-changing effect.

The bilateral removal of the centromedian nucleus (part of the Intra-laminar nucleus of the Thalamus) appears to abolish consciousness, causing coma, PVS, severe mutism and other features that mimic brain death. The centromedian nucleus is also one of the principal sites of action of general anaesthetics and anti-psychotic drugs. This evidence suggests that a functioning thalamus is necessary, but not sufficient, for human consciousness.

Neurophysiological studies in awake, behaving monkeys point to advanced cortical areas in prefrontal cortex and temporal lobes as carriers of neuronal correlates of consciousness. Christof Koch and Francis Crick argue that neuronal mechanisms of consciousness are intricately related to prefrontal cortex — cortical areas involved in higher cognitive function, affect, behavioral control, and planning. Rodolfo Llinas proposes that consciousness results from recurrent thalamo-cortical resonance where the specific thalamocortical systems (content) and the non-specific (centromedial thalamus) thalamocortical systems (context) interact in the gamma band frequency via time coincidence. According to this view the "I" represents a global predictive function required for intentionality. Experimental work of Steven Wise, Mikhail Lebedev and their colleagues supports this view. They demonstrated that activity of prefrontal cortex neurons reflects illusory perceptions of movements of visual stimuli. Nikos Logothetis and colleagues made similar observations on visually responsive neurons in the temporal lobe. These neurons reflect the visual perception in the situation when conflicting visual images are presented to different eyes (i.e., bistable percepts during binocular rivalry). The studies of blindsight — vision without awareness after lesions to parts of the visual system such as the primary visual cortex — performed by Lawrence Weiskrantz and David P. Carey provided important insights on how conscious perception arises in the brain.

An alternative and more global approach to analyzing neurophysiological (electromagnetic) correlates of consciousness is referred to by Andrew and Alexander Fingelkurts as Operational Architectonics. This hypothesis postulates that phenomenal patterns/objects/thoughts are matched with and generated by underlying neurophysiological activity's spatial-temporal patterns (indexed as Operational Modules of different complexity) that can be revealed directly from EEG.

The Neuroscience of free will also seems to provide relevant insights to the understanding of consciousness.

Measurement aspects

Experimental research on consciousness presents special difficulties, e.g., when establishing whether an observer is unaware of a critical stimulus. Several techniques exist for dissociating the conscious visibility of stimuli from indirect effects they might have on behavior. For example, the experimental technique of Response Priming allows researchers to find conditions where the conscious visibility of a critical stimulus and the ability of that stimulus to affect a motor response develop in opposite directions, e.g., when motor effects of a stimulus become larger under conditions where its visibility is decreasing.

Experimental philosophy

A new approach has attempted to combine the methodologies of cognitive psychology and traditional philosophy to understand consciousness. This research has taken place in the new field called experimental philosophy, which seeks to use empirical methods (like conducting experiments to test how ordinary non-experts think) to inform the philosophical discussion. The aim of this type of philosophical research on consciousness has been to try to get a better grasp on how exactly people ordinarily understand consciousness. For instance, work by Joshua Knobe and Jesse Prinz suggests that people may have two different ways of understanding minds generally. Another suggestion has been that there is actually no such phenomenon as consciousness, based on a criticized study by Justin Sytsma and Edouard Machery. Further, Justin Sytsma and Edouard Machery have written about the proper methodology for studying folk intuitions about consciousness.

Evolutionary psychology

Consciousness can be viewed from the standpoints of evolutionary psychology or evolutionary biology approach as an adaptation because it is a trait that increases fitness. Consciousness also adheres to John Alcock's theory of animal behavioral adaptations because it possesses both proximate and ultimate causes.

In his paper "Evolution of consciousness," John Eccles argues that special anatomical and physical properties of the mammalian cerebral cortex gave rise to consciousness. Budiansky, by contrast, limits consciousness to humans, proposing that human consciousness may have evolved as an adaptation to anticipate and counter social strategems of other humans, predators, and prey. Alternatively, it has been argued that the recursive circuitry underwriting consciousness is much more primitive, having evolved initially in premammalian species because it improves the capacity for interaction with both social and natural environments by providing an energy-saving "neutral" gear in an otherwise energy-expensive motor output machine. Another theory, proposed by Shaun Nichols and Todd Grantham, proposes that it is unnecessary to trace the exact evolutionary or causal role of phenomenal consciousness because the complexity of phenomenal consciousness alone implies that it is an adaptation. Once in place, this recursive circuitry may well have provided a basis for the subsequent development of many of the functions that consciousness facilitates in higher organisms, as outlined by Bernard J. Baars.

Functions of Consciousness

Functions of Consciousness

Function	Purpose
Definition and context-setting	Relating global input to its contexts, thereby defining input and removing ambiguities
Adaptation and learning	Representing and adapting to novel and significant events
Editing, flagging, and debugging	Monitoring conscious content, editing it, and trying to change it if it is consciously "flagged" as an error
Recruiting and control function	Recruiting subgoals and motor systems to organize and carry out mental and physical actions
Prioritizing and access control	Control over what will become conscious
Decision-making or executive function	Recruiting unconscious knowledge sources to make proper decisions, and making goals conscious to allow widespread recruitment of conscious and unconscious "votes" for or against them
Analogy-forming function	Searching for a partial match between contents of unconscious systems and a globally displayed (conscious) message
Metacognitive or self-forming function	Reflection upon and control of our own conscious and unconscious functioning
Auto-programming and self-maintenance function	Maintenance of maximum stability in the face of changing inner and outer conditions

Physical

Since the dawn of Newtonian science with its vision of simple mechanical principles governing the entire universe, some philosophers have been tempted by the idea that even consciousness could be explained in purely physical terms. The first influential writer to propose such an idea explicitly was Julien Offray de La Mettrie, in his book Man a Machine (L'homme machine).

The most influential modern physical theories of consciousness are based on psychology and neuroscience. Theories proposed by neuroscientists such as Gerald Edelman and António Damásio, and by philosophers such as Daniel Dennett, seek to explain access consciousness and phenomenal consciousness in terms of neural events occurring within the brain. Many other neuroscientists, such as Christof Koch, have explored the neural basis of consciousness without attempting to frame all-encompassing global theories. At the same time, computer scientists working in the field of Artificial Intelligence have pursued the goal of creating digital computer programs that can simulate or embody consciousness.

Some theorists—most of whom are physicists—have argued that classical physics is intrinsically incapable of explaining the holistic aspects of consciousness, but that quantum theory provides the missing ingredients. The most notable theories falling into this category include the Holonomic brain theory of Karl H. Pribram and David Bohm, and the Orch-OR theory formulated by Stuart Hameroff and Roger Penrose. Some of these QM theories offer descriptions of phenomenal consciousness, as well as QM interpretations of access consciousness. None of the quantum mechanical theories has been confirmed by experiment, and many scientists and philosophers consider the arguments for an important role of quantum phenomena to be unconvincing.

Functions

Regarding the primary function of conscious processing, a recurring idea in recent theories is that phenomenal states somehow integrate neural activities and information-processing that would otherwise be independent (see review in Baars, 2002). This has been called the integration consensus. However, it remained unspecified which kinds of information are integrated in a conscious manner and which kinds can be integrated without consciousness. Obviously not all kinds of information are capable of being disseminated consciously (e.g., neural activity related to vegetative functions, reflexes, unconscious motor programs, low-level perceptual analyses, etc.) and many kinds can be disseminated and combined with other kinds without consciousness, as in intersensory interactions such as the ventriloquism effect (cf., Morsella, 2005).

Ervin László argues that self-awareness, the ability to make observations of oneself, evolved. Émile Durkheim formulated the concept of so called collective consciousness, which is essential for organization of human, social relations. The accelerating drive of human race to explorations, cognition, understanding and technological progress can be explained by some features of collective consciousness (collective self - concepts) and collective intelligence

Tests

As there is no clear definition of consciousness and no empirical measure exists to test for its presence, it has been argued that due to the nature of the problem of consciousness, empirical tests are intrinsically impossible. However, several tests have been developed that attempt an operational definition of consciousness and try to determine whether computers and non-human animals can demonstrate through behavior, by passing these tests, that they are conscious.

In medicine, several neurological and brain imaging techniques, such as EEG and fMRI, have proven useful for physical measures of brain activity associated with consciousness. This is particularly true for EEG measures during anesthesia, which can provide an indication of anesthetic depth.

The Turing test

See also: Turing test and philosophy of artificial intelligence

Though sometimes thought of as a test for consciousness, the Turing test (named after computer scientist Alan Turing, who proposed it) was originally presented as an operational replacement for the question "Can machines think?", which Turing regarded as too ambiguous to be meaningful. This test is commonly cited in discussion of artificial intelligence. The test is based on an "Imitation Game" in which a human experimenter converses, via computer keyboards, with two competitors, one human, the other a computer. Because all of the conversation is by keyboard, no cues such as voice, prosody, or appearance will be available to indicate which is human and which is the computer. If the human judge is unable to determine which of the conversants is the computer, the computer is said to have "passed" the test.

The Turing test has generated a great deal of philosophical debate. For example, Daniel Dennett and Douglas Hofstadter argue that anything capable of passing the Turing test is necessarily conscious, while David Chalmers, argues that a philosophical zombie could pass the test, yet fail to be conscious.

It has been argued that the question itself is excessively anthropomorphic. Edsger Dijkstra commented that "The question of whether a computer can think is no more interesting than the question of whether a submarine can swim", expressing the view that different words are appropriate for the workings of a machine to those of animals even if they produce similar results, just as submarines are not normally said to swim.

Philosopher John Searle developed a thought experiment, the Chinese room argument, which is intended to show problems with the Turing Test. Searle asks the reader to imagine a non-Chinese speaker in a room in which there are stored a very large number of Chinese symbols and rule books. Questions are passed to the person in the form of written Chinese symbols via a slot, and the person responds by looking up the symbols and the correct replies in the rule books. Based on the purely input-output operations, the "Chinese room" gives the appearance of understanding Chinese. However, the person in the room understands no Chinese at all. This argument has been the subject of intense philosophical debate since it was introduced in 1980, even leading to edited volumes on this topic alone.

The application of the Turing test to human consciousness has even led to an annual competition, the Loebner Prize, with "Grand Prize of $100,000 and a Gold Medal for the first computer whose responses were indistinguishable from a human's."

Mirror

Main article: Mirror test

See also the concept of the Mirror stage by Jacques Lacan

With the mirror test, devised by Gordon Gallup in the 1970s, one is interested in whether animals are able to recognize themselves in a mirror. The classic example of the test involves placing a spot of coloring on the skin or fur near the individual's forehead and seeing if they attempt to remove it or at least touch the spot, thus indicating that they recognize that the individual they are seeing in the mirror is themselves. Humans (older than 18 months) and other great apes, bottlenose dolphins, pigeons, elephants and magpies have all been observed to pass this test. The test is usually carried out with an identical 'spot' being placed elsewhere on the head with a non-visible material as a control, to assure the subject is not responding to the touch stimuli of the spot's presence.

Delay

One problem researchers face is distinguishing nonconscious reflexes and instinctual responses from conscious responses. Neuroscientists Francis Crick and Christof Koch have proposed that by placing a delay between stimulus and execution of action, one may determine the extent of involvement of consciousness in an action of a biological organism.

For example, when psychologists Larry Squire and Robert Clark combined a tone of a specific pitch with a puff of air to the eye, test subjects came to blink their eyes in anticipation of the puff of air when the appropriate tone was played. When the puff of air followed a half of a second later, no such conditioning occurred. When subjects were asked about the experiment, only those who were asked to pay attention could consciously distinguish which tone preceded the puff of air.

Ability to delay the response to an action implies that the information must be stored in short-term memory, which is conjectured to be a closely associated prerequisite for consciousness. However, this test is only valid for biological organisms. While it is simple to create a computer program that passes, such success does not suggest anything beyond a clever programmer.

Merkwelt

The merkwelt (German; English: "way of viewing the world", "peculiar individual consciousness") is a concept in robotics, psychology and biology that describes a creature or android's capacity to view things, manipulate information and synthesize to make meaning out of the universe.

In biology, a shark's merkwelt for instance is dominated by smell due to its enlarged olfactory lobes whilst a bat's is dominated by its hearing, especially at ultrasonic frequencies. In literature, a character's merkwelt can be defined by their particular consciousness. For the collective, the plural is merkwelten. It is related to the original German meaning of zeitgeist and indeed a merkwelt can be thought of as a more general, individual zeitgeist.

To have a merkwelt, the individual must be self-aware. This "self-awareness" may involve thoughts, sensations, perceptions, moods, emotions, and dreams. This term was particularly developed by the German biologist Jakob von Uexküll who framed it as part of his theory of umwelt. This basically stated that any living 'observer' of the broader environment or umwelt through their particular werkwelt or 'mechanical viewing' (that is to say, the organs through which they view the world- their eyes, ears, mouth etc. in humans and electrical sensors in sharks for instance) could have a merkwelt or 'perceptual universe'. In essence, his theory posits that the way each human or certain type of aware animal perceives of their environment both through their experiences, the particular way their organs perceive their environment and the way in which their consciousness processes this information (how their brain works).

See also

Cognitive science

• Attention
• Binocular rivalry
• Blindsight
• Change blindness
• Cognitive science
• Iconic memory
• Level of consciousness
• Multistable perception
• Neural correlates of consciousness
• Neural Darwinism
• Primary consciousness
• Psyche (psychology)
• Response Priming
• Reticular activating system
• Short term memory
• Society of Mind
• Split brain
• Stream of consciousness (psychology)
• Unconscious mind
• Visual short term memory

Spirituality

• Vijñāna (viññāṇa) — consciousness as a concept in Buddhism
• Higher consciousness
• Mindstream
• Krishna consciousness or bhakti
• Quantum mysticism - supposes consciousness has a mystical component at the quantum scale

Physical hypotheses about consciousness

• Orch-OR theory
• Electromagnetic theories of consciousness
• Holonomic brain theory
• Quantum mind
• Simulated Reality
• Externalism

Philosophy

• 8-Circuit Model of Consciousness
• Bodymind
• Donald Davidson's swamp man thought experiment ("Knowing One Own's Mind", 1987)
• Dream argument
• False Consciousness (Marxism)
• Freedom of thought
• Homunculus
• Mental body
• Mind
• Mind at Large
• Mind-body problem
• Multiple Drafts theory (Daniel Dennett) cf. also Marvin Minsky
• New Mysterianism
• Personhood Theory
• Philosophy of mind
• Philosophy of perception
• Political consciousness, pertaining to marxist and post-marxist conceptions of consciousness.
• Qualia
• Stream of consciousness
• Supervenience
• Theory of mind
• Aboutness

Sociology and Socio-linguistics

• Sociology of human consciousness

Groups

• Association for Consciousness Exploration
• Association for the Scientific Study of Consciousness
• Mind and Life Institute
• Mind Science Foundation
• Sackler Centre for Consciousness Science

References

• Block, N., Flanagan, O., & Güzeldere, G. (1997). The Nature of Consciousness: Philosophical debates Cambridge, MA: MIT.
• Carruthers, P. (2007). In Stanford Encyclopedia of Philosophy. (version Sep 11, 2007) http://plato.stanford.edu/entries/consciousness-higher/
• Farthing, G. W. (1992). The Psychology of Consciousness. Upper Saddle River, NJ: Prentice Hall.
• van Gulick, R. (2004). Consciousness. In Stanford Encyclopedia of Philosophy. (version Aug 16, 2004) http://plato.stanford.edu/entries/consciousness/
• Nagel, T. (1974). What it is like to be a bat. Philosophical Review 83. October, 435-450.
• Searle (2005). Consciousness. In Honderich, T. (Ed.) (2005). The Oxford Companion to Philosophy (2nd ed.). Oxford.
• Velmans, M., & Schneider, S. (Eds.) (2007). The Blackwell Companion to Consciousness. Malden, MA: Blackwell.
• McKenna, T., McKenna, D. (1975). "The Invisible Landscape - Mind, Hallucinogens, and I Ching". Seabury Press.

Further reading

• Baars, B. (1997) In the Theater of Consciousness: The Workspace of the Mind. New York, NY: Oxford University Press. 2001 reprint: ISBN 978-0-19-514703-2
• Baars, Bernard J and Stan Franklin. (2003) How conscious experience and working memory interact. Trends in Cognitive Science 7: 166–172.
• Yaneer Bar-Yam (2003). Dynamics of Complex Systems, Chapter 3. {{cite book}}: External link in |title= (help)
• Blackmore, S. (2003) Consciousness: an Introduction. Oxford: Oxford University Press. ISBN 978-0-19-515343-9
• Blackmore, S. (2005) "Conversations on Consciousness". Oxford: Oxford University Press. ISBN 978-0-19-280623-9
• Block, N. (2004). The Encyclopedia of Cognitive Science.
• Carter, Rita. (2002) Exploring Consciousness. UC Berkeley Press. ISBN 0-520-23737-4
• Chalmers, D. (1996) The Conscious Mind: In Search of a Fundamental Theory. New York: Oxford University Press. ISBN 978-0-19-511789-9
• Chalmers, D. (2002) The puzzle of conscious experience. Scientific American, January 2002. [2]
• Cleermans, A. (Ed.) (2003) The Unity of Consciousness: Binding, Integration, and Dissociation. Oxford: Oxford University Press. ISBN 978-0-19-850857-1
• Rodney M. J. Cotterill (1998). Enchanted Looms : Conscious networks in brains and computer. Cambridge University Press. ISBN 978-0521794626.
• Crick, F.H.C. (1994) "The Astonishing Hypothesis". London Simon & Schuster Ltd. ISBN 0-671-71295-0
• Eccles, J.C. (1994) How the Self Controls its Brain, (Springer-Verlag).
• Franklin, S., B.J. Baars, U. Ramamurthy, and Matthew Ventura. (2005) The role of consciousness in memory. Brains, Minds and Media 1: 1–38, pdf.
• Halliday, Eugene, Reflexive Self-Consciousness, ISBN 0-872240-01-1
• Harnad, S. (2005) What is Consciousness? New York Review of Books 52(11).
• Harnad, S. (2008) What It Feels Like To Hear Voices: Fond Memories of Julian Jaynes
• James, W. (1902) The Varieties of Religious Experience
• Immanuel Kant (1781). Critique of Pure Reason. Trans. Norman Kemp Smith with preface by Howard Caygill. Pub: Palgrave Macmillan.
• Kelly, Edward F., Emily Williams Kelly, Adam Crabtree, Alan Gauld, Michael Grosso, and Bruce Greyson (2007). Irreducible Mind: Toward a Psychology for the 21st Century, Lanham, MD: Rowman & Littlefield, xxxi + 800 pp. ISBN 978-0-7425-4792-6
• John Locke (1689). An Essay Concerning Human Understanding
• Libet, B., Freeman, A. & Sutherland, K. ed. (1999) The Volitional Brain: Towards a neuroscience of free will. Exeter, UK: Short Run Press, Ltd.
• Llinas R.,Ribary, U. Contreras, D. and Pedroarena, C. (1998) "The neuronal basis for consciousness" Phil. Tranns. R. Soc. London, B. 353:1841-1849
• Llinas R. (2001) "I of the Vortex. From Neurons to Self" MIT Press, Cambridge
• Metzinger, T. (2003) Being No One: the Self-model Theory of Subjectivity. Cambridge, MA: MIT Press.
• Metzinger, T. (Ed.) (2000) The Neural Correlates of Consciousness. Cambridge, MA: MIT Press. ISBN 978-0-262-13370-8
• Morgan, John H. (2007) In the Beginning: The Paleolithic Origins of Religious Consciousness. Cloverdale Books, South Bend. ISBN 978-1-929569-41-0
• Morsella, E. (2005) The Function of Phenomenal States: Supramodular Interaction Theory. Psychological Review, 112, 1000-1021.
• Neumann, Erich. The origins and history of consciousness, with a foreword by C.G. Jung. Translated from the German by R.F.C. Hull. New York : Pantheon Books, 1954.
• Penrose, R., Hameroff, S. R. (1996) 'Conscious Events as Orchestrated Space-Time Selections', Journal of Consciousness Studies, 3 (1), pp. 36–53.
• Peters, Frederic (2008) "Consciousness as Recursive, Spatiotemporal Self-Location" http://precedings.nature.com/documents/2444/version/1
• Pharoah, M.C. (online) Looking to systems theory for a reductive explanation of phenomenal experience and evolutionary foundations for higher order thought Retrieved December 14, 2007.
• Sanz, R., López, I., Rodríguez, M. and Hernández, C. (2007) 'Principles for Consciousness in Integrated Cognitive Control'. Neural Networks, 20, pp. 938–946.
• Scaruffi, P. (2006) The Nature Of Consciousness. Omniware.
• Searle, J. (2004) Mind: A Brief Introduction. New York: Oxford University Press.
• Sternberg, E. (2007) Are You a Machine? The Brain, the Mind and What it Means to be Human. Amherst, NY: Prometheus Books.
• Tolle, Eckhart (1999) The Power of Now: A Guide to Spiritual Enlightenment. New World Library. pp 36–37. ISBN 978-1-57731-152-2
• Velmans, M. (2000) Understanding Consciousness. London: Routledge/Psychology Press.
• Velmans, M. and Schneider, S. (Eds.)(2006) The Blackwell Companion to Consciousness. New York: Blackwell..

External links

Academic journals & newsletters

• Anthropology of Consciousness
• Journal of Consciousness Studies
• Consciousness and Cognition
• Psyche
• Science & Consciousness Review
• ASSC e-print archive containing articles, book chapters, theses, conference presentations by members of the ASSC.

Philosophy resources

• Publications of the Tufts Center for Cognitive Studies, including Daniel Dennett
• David Chalmers' directory of online papers on consciousness
• Intuitions about Consciousness: Experimental Studies an article describing the folk intuitions about what is a conscious agent
• Stanford Encyclopedia of Philosophy:
  • Consciousness (General)
  • Animal Consciousness
  • Higher Order Theories of Consciousness
  • Consciousness and Intentionality
  • Representational Theory of Consciousness
  • Unity of Consciousness
• Internet Encyclopedia of Philosophy:
  • Consciousness
  • Higher-Order Theories of Consciousness

Miscellaneous sites

• You won't find consciousness in the brain (on why consciousness cannot be measured or grasped by the same scientific methods and techniques as the brain)
• What Consciousness is: A Definition and Framing of the Problem
• History of Consciousness Graduate Program, ("consciousness as forms of human expression and social action manifested in historical, cultural, and political contexts") at the University of California, Santa Cruz, headed by Dr. Angela Davis* Online lecture videos, from an undergraduate course taught by Christof Koch at Caltech on the neurobiological basis of consciousness in 2004.
• Piero Scaruffi's annotated bibliography on the mind
• Looking into the mystery of life how science fails to reach consciousness.
• Anesthesia and Drug effects on consciousness
• Brain Atlas, Brain Maps, Neuroinformatics
• Online course in consciousness at University of Virginia
• A survey course at University of Florida
• Edinburgh thesis (.ps) on consciousness including up-to-date reviews
• The Mystery of Consciousness TIME.com
• Helen Keller Language and Consciousness

Radio

• Consciousness on In Our Time at the BBC

Video

• Jill Bolte Taylor - My Stroke of Insight
• Christof Koch, Noam Chomsky, Pat Churchland, David Glanzman, David Chalmers- The Mystery of Consciousness